1. Field of the Invention
This invention relates to structures, in particular tall buildings. It is a way of constructing a tall structure such that failure of part of the structure that results in a collapse above the failure does not cause a total collapse of the structure.
2. Background Information
Tall buildings have a strong generally vertical structure designed to resist the force of gravity and generally diagonal and horizontal struts working in concert with the weight-carrying structure to resist side loads due to wind, earthquakes impact etc. Within this framework floors must be supported if the structure is a multi-floored building. Any given piece of the structure can perform multiple functions, depending on the particular design. If a failure of a member occurs loads are transferred to other members and no overall failure occurs if these are not over loaded to the point of failure. Total failure of the structure can occur however if the overloaded members fail and the process continues. This is what happens in a tall building if upper floors and related structure collapse into the floors and structure below. Increasing overload occurs and the total structure collapses virtually completely.
In a conventional structure the floors are attached to the vertical supports and each floor has a factor of safety for unexpected high loads. However, it simply is not practical to have each floor so strong that it can with stand the impact of floors and other structure falling from above.
The collapse of the World Trade Center on Sep. 11, 2001, sadly shows the potential result of a failure in a conventionally constructed building. The intent of this invention is to greatly reduce such a possibility in future large, tall structures.